1. Field of the Invention
This invention relates generally to seat cushions, and particularly to seat cushions of the type commonly used in conjunction with wheelchairs.
The invention is not necessarily limited to wheelchair seating, as the cushions could be used in any desired seating application. However, the cushions are particularly useful in wheelchair seating, to reduce pressure exerted on the ischial tuberosities and sacral region, to prevent tissue trauma, and to reduce the probability of pressure sores, decubitis ulcers, and other well-documented problems associated with confinement to a wheelchair.
The preferred embodiment of the invention incorporates a pad which contains a viscous fluid.
2. Description of the Prior Art
Seat cushions incorporating fluid-filled pads are well known. See for example U.S. Pat. Nos. 4,588,229, 4,660,238, 4,726,624 and 4,761,843. In some such cushions, for example the ones described in U.S. Pat. Nos. 4,588,229 and 4,726,624, the pad is divided into compartments, each containing a fluid. The separate compartments are provided to prevent all of the fluid in the pad from flowing to one side such that the individual could "bottom out" on the seating platform. The pads are permanently sealed both peripherally and between compartments, so that there is no flow of fluid between the compartments, nor any possibility of adjusting the volume of fluid.